Heat exchange apparatus



Sept. 25, 1951 w. KALS 2,568,891

HEAT EXCHANGE APPARIATUS 3 Sheets-Sheet 1 Filed Oct. 26, 1945 a/am BY j J A'ITORNEYSTF INVENTOR Sept. 25, 1951 w, s 2,568,891

HEAT EXCHANGE APPARATUS Filed Oct. 26, 1945 3 Sheets-Sheet 2 INVENTOR 60% M x 3% w M4 ATTORNEYS Sept. 25, 1951 w. KALS HEAT EXCHANGE APPARATUS 3 Sheets-Sheet 3 Filed Oct. 26, 1945 mmrm W Patented Sept. 25, 1951 HEAT EXCHANGE APPARATUS Walter Kala, New York, N. Y., assignor to Niagara Blower Company, New York, N. Y., a corporation of New York Application October 26, 1945, Serial No. 624,841

Claims. (Cl. 261-11) This invention relates to heat exchange apparatus and more particularly to apparatu for cooling and dehumidifying gases used in processing other materials.

In various processes, particularly heat treating processes, it is desirable to effect a part of the processing in a chemically inert atmosphere to avoid undesired chemical reactions. For example, in the heat treating of certain metals, it is desirable to maintain an inert atmosphere in the heat treating furnace to avoid scaling or other undesired surface change of the metal parts under treatment. Further, in the processing of oils it is desirable to effect a part of the processing in a chemically inert atmosphere. Such chemically inert atmospheres are frequently maintained at a higher than atmospheric pressure so that there is no danger of contamination through leakage, any leakage merely resulting in loss of the chemically inert gas but not resulting in contamination of the atmosphere.

The chemically inert gas for such atmospheres is generally produced by the incomplete combustion of gaseous fuels, containing hydrocarbons, to provide carbon monoxide. As an example, the reaction in th incomplete combustion of methane is as follows:

As will be seen, the reaction involves the production of quantities of water the presence of which in the inert atmosphere is harmful in producing blemishes, stains and other undesired effects. The moisture in the gas can be removed chemically by adsorbents, such as silica gel, activated alumina and the like or absorbents, such as lithium chloride brine, but such chemical removal requires reactivation of the adsorbent or absorbent thereby to require a cycling operation.

-It is accordingly one of the principal objects of the present invention to effect the continuous dehumidification of gases under pressure to a very low dewpoint so as t provide an atmosphere having a very low moisture content.

Another object is to provide apparatus for the continuous dehumidification of gases under pressure t a very low dewpoint which is simple in construction and operation and which requires little supervision.

Another object is to provide such apparatus which can be readily set to maintain the exact degree of dehumidification desired.

Another object is to provide such apparatus which can be readily cleaned to maintain constant operation conditions.

Another object is to provide such an apparatus in which the gas under pressure is cooled t a low temperatur to effect the condensation and removal of the moisture and in which there is no ent invention.

Fig. 2 is a vertical central section through one form of spray chamber and sump tank embodying the invention.

Fig. 3 is an end elevation of the apparatus shown in Fig. 2.

Figs. 4 and 5 are vertical sections, taken on the correspondingly numbered lines of Fig. 2.

Fig. 6 is a side elevation, partly broken away,

of a modified form of spray chamber.

Figs. 7 and 8 are vertical sections, taken on the correspondingly numbered lines of Fig. 6.

In the form of the invention shown in Figs. 1-5, the gas under pressure is cooled by passing it through a cylindrical spray chamber ill in which cooling coils are arranged so that the leaving temperature of the gas can be, say 45 F. With such a reduction intemperatur of the gas the preponderance of its moisture is precipitated when passing through the spray chamber and hence upon reheating the leaving gas it is rendered substantially dry and capable of being used where substantially moisture-free gas is required. To prevent the removed moisture from condensing upon the cooling coils in the spray chamber I8, these coils are continuously Washed by sprays, the spray liquid collecting and being recirculated from a sump tank below the spray chamber. This spray liquid is preferably a liquid of low freezing point which is miscibl with water and to maintain the desired 10w freezing point of the mixture, which is, of course, being constantly diluted by the moisture removed from the gas, a reconcentrator is provided.

The spray chamber, as shown in Figs. 1-5, is preferably constructed as follows:

The numeral ll represents a cylindrical shell which is formed to provide an integral end head l2. The opposite open end of this shell is flanged, as indicated at l3, and to this flange a removable end head I4 can be secured in any suitable manner. Adjacent the end head 2i the spray chamber is provided with a radially extending inlet '5 through which the gas under pressure is admitted to the casing II], this inlet being shown a extending upwardly. At its opposite end the shell II is provided with an upwardly extending gas outlet and which is shown as provided with eliminator plates so that the leaving gas is whipped back and forth so as to remove any entrained moisture therefrom.

eral tubes connect with an outlet header 2| hav-' ing a suction line 24 extending throughthe removable end head It will be understood that a suitable gas-tight Joint is provided around the tube ends 22 and the suction line 2| to prevent leakage of the gas from the chamberll. The

horizontal legs of the tubes 2| are provided with spaced rectangular fins 25, the legs of the several 'tubes 2| extending through openings provided in each fin and good thermal contact being obtained by expanding the tubes 2| in these Openings. The fins extend transversely of the shell ii and are substantially smaller than the shell. The gas cylindrical shell so that the Basis prevented from escaping through these spaces and is compelled to pass through the bank of expansion coils.

It will be seen that the finned expansion coil 2|, together with the bailies A and B welded thereto. is removable as a unit with the end head ll, it being merely necessary to remove the fastening members for the end head following which the entire cooling coil and bame assembly can be removed as a unit axially from the cylindrical shell The spray pipe 45, together with it nozzles 4|, are similarly removable from the cylindrical shell II as a unit with the end head expansion coil 2| and bailles A and B. For this purpose the spray pipe 45 is introduced through the removable end head II and extends through openings 4| provided in each of the bailies B. The spray nozzles 4| are arranged between each pair of the bailles B and between the end battles B and the end heads of the cylindrical shell so that all parts of the expansion coil 2| and its fins 25 are washed with the spray liquid. This spray liquid collects in the bottom of the cylindrical shell and flows to a bottom central outlet 4| for the cylindrical shell II, this fiow being permitted by the notches 22 provided in the passing through the spray chamber is diverted to pass transversely across the legs of the tubes 2| a plurality of times before being discharged through the outlet For this purpose bailies, designated at A and B, are provided, these bailies A and B being arrangeddn alternation.

As best shown in Fig.4 each baflle A comprises a sheet of metal 2| having sides 2| and a lower cross piece 2|. The opposing vertical edges 32 of the sides 2| and the upper edge of the cross piece 3| are rectangular and fit the corresponding edges of any of the rectangular fins 25 of the expansion coil 2|. 'lheouter edge ll formed by the sides 2| and the cross piece is of semicircular form to fit the sides and bottom of the cylindrical shell II. The sides 2| preferably extend above the fins 25 of the expansion coil. as best shown in Pig. 4. The cross piece II is provided in its under edge with a plurality of notches 32 which permit the spray liquid to drain along the bottom of the shell II, as hereinafter described. The plates 2| are welded to the side and bottom edges bottoms of the bailies A.

-The spray liquid outlet 0 connects with the inlet 5| of an enclosed cylindrical sump tank 5| which can have a sight glass. 52 and a normally closed drain 52. The outlet 5| from this sump tank is shown as connected by a line 55 with the inlet of a pump 5| driven by an electric motor 5|.

The outlet line 5| from the pump 5| is connected .by a branch line with the spray pipe II, a

valve being provided in the branch line N to regulate the flow of spray liquid to the spray pipe 55 and its nozzles 45.

of the fins 25 at spaced intervals along the expansion coil 2|.

As best shown in Fig. 5 each baille B comprises a sheet of metal 85 having sides 3| and an upper cross piece 3|. The opposing vertical edges of the sides 3| and the lower edge of the cross piece are rectangular and fit the corresponding edges of any of the rectangular fins 25 of the expansion coil 2|. The outer edge 3| formed by the sides 35 and the cross piece 2| is of semicircular form to fit the sides and top of the cylindrical shell The lower edges 4| of the sides 3| are horizontal and are coplanar with the lower edges of the fins 25 of the expansion coil. The plates 35 are welded to the side and top edges of the fins 25 at spaced intervals and midway between the bafiies A.

In order to insure that the air" passes over the coil 2| a plurality of angle pieces 4| are arranged along the opposite lower corners of the fins 25 between the baiiies A and extending lengthwise of the spray chamber The sides of these angle bars fit the cylindrical interior of the shell II and thereby block the spaces between the Itwillbeseenthatthepump5|providesa constant recirculation of the spray liquid, this pump forcing the spray liquid through its outlet line 5| and the branch line to the spray pipe from which this liquid is discharged in the form of sprays from the nonles 0 against the fins and tubes of the expansion coil 2|. The spray liquid collects in the bottom of the cylindrical shell II and flows through the notches 22 provided in the several baiiies A to" the outlet 4| where it flows down into the sump tank 5|. From this sump tank the spray liquid is withdrawn through the outlet 54 and line 55 to the inlet of the pump 5| where it is again recirculated.

As previously indicated the expansion coil 2| is maintained at a very low temperature, in the order of F., so as to provide a leaving gas temperature in the outlet of the assumed -45 1". This is for the purpose of reducing the dewpoint of the gas to -45 I". so that when this gas is reheated it is substantially free from moisture. The moisture removed by cooling the air to this low temperature in the spray chamber I. is added to the spray liquid being recirculated by the pump 5| and hence the spray liquid becomesincreasingly dilute as the dehydration of the gas takes place. Such dilution would ultimately extend to the point where the diluted spray liquid would freeze on the expansion coil 2| and its fins 25 and hence automatic reconcentration of the spray liquid is required to maintain it at the required strength and to remove the water condensed from the gas under treatment.

To this end the antifreeze component of the lower corners of the group of fins 25 and the I. spray liquid has a substantially higher boiling point than water and is reconcentrated by the apparatus illustrated in Fig. 1, this apparatus being constructed as follows:

The outlet line 59 from the pump 56 is provided with a branch 65 leading through a heat exchanger 66 to a boiler or concentrating tank 68. The spray liquid in this concentrating tank 68 is heated in any suitable manner to vaporize the water contained in the spray liquid. The water vapors pass out through a bubble tower which is preferably constructed in accordance with the Olstad Patent No. 2,352,655, this bubble tower preventing the loss of any substantial quantity of the antifreeze component. The concentrated liquid from the concentrating tank 68 passes through the heat exchanger 66 in heat exchange relation with the incoming liquid and flows through a line I8 to an open tank 1|.

The line 65 is provided with a hand valve 12 and a strainer 13 and the amount of liquid flowing through this pipe is proportioned to the degree of dilution effected by the passage of the gas through the spray chamber |8. To this end a solenoid valve H is provided in the line 65, this solenoid valve being connected by an electric line 15 with an electrical controller 16, this electrical controller being operated in response to the vertical movement of a float arm 18 in the sump tank and opening or closing the solenoid valve 14. As dilution occurs the level of liquid in the sump tank 5| rises, this lifting the float arm 18 and actuating the electric controller to open the solenoid valve M. In consequence a proportion of spray liquid is forced by the pump 56 through its outlet line 59 and branch 65 into the concentrating tank 88 where heat is applied to drive off the excess water, the concentrate being returned through the line I8 to the open tank II.

This open tank H is in turn provided with an electric controller 19 whichis actuated in response to a float arm 88. The electric line 8| from the electric controller 19 connects with an electric motor 82 driving a pump 83, the inlet 84 of this pump being connected with the bottom of the open tank The outlet line 85 from the pump 83 is shown as provided with a hand valve 86 and strainer 88 and is shown as discharging into the sump tank 5|. A branch 89 from the electrical control line of the electric controller 19 connects with a solenoid valve 98 in the pump outlet line 85. When the level of the liquid in the open tank 1| rises above a predetermined level the float arm 88 actuates the controller 19 to energize the electric motor 82 and to open the solenoid valve 90. In consequence the concentrated spray liquid is drawn by the pump 83 from the open tank 14 and discharged through its outlet line 85 into the sump tank 5|. When the level in the open tank II is restored to the setting of the electric controller 19 this controller deenergizes the motor 82 and also closes the solenoid valve 19. The closing of the solenoid valve 19 prevents back pressures from developing in the line 85, the gas "introduced into the spray chamber I8 being under a positive pressure.

In the operation of the form of the invention shown in Figs. 1-5, the gas, such as carbon monoxide obtained by the incomplete combustion of hydrocarbons such as methane and saturated with the water resulting from the incomplete combustion, is introduced under pressure at a temperature of, say, 90 F. through the inlet l5 of the spray chamber l8. This gas passes downpasses underthe lower edge or this .baille B.

Since the inner edges of this baflle B are welded of the expansion coil. 28. The bypassing of any a of this gasaround the lower corners of the fins 25 is prevented by the adjacent endmost pair of angle bars 4| which are welded to the opposite lower corners of the fins between the baffles A. On passing under the firstbaflie B the air is deflected upwardly by the next succeeding baflle A. This baille A has its outer semi-circular edge 3| fitted to the interior of 'the cylindrical shell andconsequently the gas cannot escape therearour'id; "-Its inner edges are welded to the adjacent on -the fins 25 of the expansion coil 28, onsequence the gas returns upwardly, flowing tranyersely of the legs of the expansion coil Zqgand among the several fins 25 arranged between thefirst baflle B and the next succeeding baflle iA.; .-'Similar baflles A and B are secured in alternation 'at spaced intervals to the fins 25 of the expansion coil and hence the gas is deflected to pass vertically back and forth transversely across the expansion coil 28 and among its fins 25 before this gas can reach the outlet Hi from the spray chamber l8. The expansion coil is maintained at a temperature of, say, 50 F. so that the temperature of the gas leaving the outlet [S is in the order of 45 F. On reheating this gas having a dewpoint of -45 F., it is substantially dry and can be used as the inert atmosphere in furnaces, oil processing and the like without danger of injury to the product because of an excessive moisture content.

On being reduced to this low temperature by the expansion coil 28 and its fins 25, the moisture originally present in the gas is condensed and to prevent the freezing of this condensate on the expansion coil 28 and its fins 25, the finned coil assembly is continuously washed with a spray liquid comprising an anti-freeze liquid having a boiling point substantially higher than water. This liquid is discharged from the spray pipe 45' through the nozzles 45 against the finned expansion coil 28, this liquid collecting in the bottom of the cylindrical shell and flowing out through its outlet 49 into the sump tank 5|. The

lower edges of the baflles A are notched as at 33, to permit the flow of spray liquid along the bottom of the cylindrical tank The spray liquid in the sump tank "5| is Withdrawn by the spray liquid pump 56 through the sump tank outlet 54 and line 55. This spray liquid is returned to the spray pipe 45 through the line 59 and branch 68.

Excessive dilution of the spray liquid must be prevented since otherwise this spray liquid would freeze upon the expansion coil 28 and its fins 25. To this end the float arm 18 is provided in the sump tank 5|, this float arm actuating the electrical controller 16 to open and close the solenoid valve 14 in the branch line 65 leading from the outlet line of the spray Water pump 56 through the heat exchanger 66 to the concentrating tank 68. In this concentrating tank 68 heat is applied to vaporize the water, the water vapor passing out through the bubble tower '69. The concentrated liquid returns through the heat exchanger 66 and line HJ'to the open tank '|l. When the level of the liquid in the tank rises beyond a predeterwardly between the adjacent baflles A and B and mined'level, the float arm 88 therein actuates the electrical controller 19 to energize the electric motor 02 and to open the solenoid valve 00. The pump 83 is thereby actuated to withdraw the spray liquid from the open tank II through the pump inlet 84 and to discharge this liquid through the pump outlet line 05 and open solenoid valve so into the sump tank BI, thereby to return the concentrated spray liquid to the spray system.

A feature of the invention resides in the construction of the spray chamber I0. It will be noted that the cylindrical form of this spray chamber permits of handling gases at high pressures. At the same time the arrangement of the battles A and B therein insures maximum heat transfer between the gas and the finned expansion coil 20, so that a minimum of surface is required, thereby to provide a compact unit capable of handling a, large volume of gas at higher than atmospheric pressures. It will further be seen that the spray liquid pipe 45 is compactly arranged in the cylindrical spray tank I to adsquately flood the expansion coil 20 and its fins 25 with the spray liquid to prevent freezing of the concentrate thereon and it will be seen that the diluted spray liquid readily escapes from the cylindrical spray chamber II to a separate sump tank for recirculation through the sprays. It will also be noted that the entire refrigerating coil, baffle structure and spray water pipe 45 can be readily removed from the spray chamber I0 by the simple expedient of removing the removable end head I4 thereof and withdrawing this composite structure axially from the tubular shell II which forms the main enclosure of the spray chamber I0.

The modified form of spray chamber shown in Figs. 6-8 comprises a cylindrical shell BI having an integral end head 92 at one end and having its opposite open end surrounded by an annular outwardly projecting flange 93. This open end of the cylindrical shell 9| can be closed by a removable end head 94 which can be detachably secured to the flange 03 in any suitable manner. The inlet 95 for the gas extends upwardly from the cylindrical shell 9| adjacent the end head 92 and the gas outlet 96 extends upwardly from the cylindrical shell 0| adjacent to the removable end head 94. As with the gas outlet I! in the form of the invention shown in Figs. 1-5, the gas outlet 96 can be provided with eliminatorplates 90 to remove any entrained moisture from the gas.

As with the form of the invention shown in Figs. 1-5, an expansion coil I00 is arrangedin the shell 9|, this expansion coil comprising a'plurality of serpentine tubes III, the inlet ends I02 of which extend through the removable end head 94 and can be connected to a multiple outlet expansion valve (not shown). Th opposite ends of the serpentine tubes I0l connect with a header I03 having a suction line I 04 extending through the removable end head 04. The horizontal legs of the-tubes IOI are expanded into the openings of a plurality of rectangular fins I05 providedin regularly spaced relation along the horizontal legs of these tubes.

The bank of fins I05 are embraced by plates I00 which fit the opposite vertical sides of these fins at I05 and extend the full length of the cylindrical shell SI and its end heads 92 and 04 so as to block oil the opposite sides of this shell and provide a straight sided passage through the center of this shell and in which the bank of fins oi the expansion coil I00 is fitted. These side plates I" can be provided withupper flanges Ill and 8 cylindrical shell 0| and can be welded thereto. However. these side plates can also be welded to the edges of the fins I" of the expansion coil I00.

To provide bailies similar to the bailes A and B of the form of the invention shown in Figs. 1-5, a plurality of small bailies C are welded at spaced intervals to the lower edges oi the fins III of the expansion coil at spaced intervals therealong. These baifles C extend downwardly and fit the bottom of the cylindrical shell II as well as the adjacent vertical sides of the side plates I". These baiiles C have their lower edges notched, as indicated at III, to permit the fiow of spray water along the bottom of the cylindrical shell I I.

Intermediate these baiiles C, bailies D are welded to the upper edges of the fins I00 of the expansion coil I00. These baiiles D extend upwardly to fit the curving top of the cylindrical shell 0i and have straight vertical sides fitting the side plates I00. These baihes D are penetrated by the spray pipe Iii which has spray nozzles I Ii disposed to flood the entire expansion coil I00 and its fins I05 with the antifreeze liquid. As with the form of the invention shown in Figs. 1-5, this spray pipe II extends through the removable end head 04 so that the entire structure of expansion coil I00, its fins I05, the baIIics C and D, and the spray pipe structure can be removed by the simple expedient of removing the removable end head 04 and withdrawing this entire structure axially from the cylindrical shell 9|. A spray liquid outlet III is provided in the bottom of the shell 0| to permit the spray liquid to escape therefrom, such escape being permitted by the notches I II inthe bailies C.

It will be seen that the form of spray chamber shown in Figs. 6-8 operates in substantially the same manner as the spray chamber shown in Figs. 1-5. Thus, the .warm moist gas entering the cylindrical shell 0| is forced by the bailies C and D, and the fins I05 to which they are welded, to whip back and forth transversely across the expansion coil I00 and among the fins I" provided thereon. It will further be seen that adequate provision is made for the flooding of the expansion coil and its fins I08 with an antifreeze liquid and for the escape of this liquid from the shell. It will also be seen that this shell II is designed to withstand high pressures and that the entire cooling, air billing and spray assembly can be removed as a unit by the simple expedient of removing the end head 04 and withdrawing this assembly.

From the foregoing it will be seen that the present invention provides an efilcient apparatus for dehydrating gases under pressure, particularly carbon monoxide produced by the incomplete combustion of methane and with the resulting production of water. It will further be seen that the structure, particularly the spray chamber, is extremely compact and readily accessible for cleaning. The apparatus is also continuous in its operation, as compared with ab sorption or adsorption systems and can be readily operated by anyone familiar with refrigeration, thereby to elimiate the necessity for special information in its operation.

- I claim as my invention:

1. In apparatus for cooling and dehumidifying gas under substantially higher than atmospheric pressure, a pressure-tight shell having an inlet at one end for gas under pressure and an outlet lower flanges I III which engage the interior of the II for said gas at it ite a li 1 "a ranged in a said shell and having an inlet and an outlet extending through said shell, fins fast to said cooling coil and forming an extended surface thereon, baffles in said shell each closely fitting the greater part of the internal cross sectional area of said shell, said bafiies being alternately provided with apertures on opposite sides of said shell to deflect the gas to pass back and forth a plurality of times across said cooling coil and parallel with the fins thereof, a spray pipe extending through said shell above said cooling coil and through apertures in said bafiles and supplied with an antifreeze liquid, downwardly directed nozzles on said spray pipe discharging said liquid against said fins to prevent frosting thereof, an outlet for the spray liquid in the bottom of the shell and means for recirculating the spray liquid from said spray liquid outlet through said nozzles.

2. In apparatus for cooling and dehumidifying gas under substantially higher than atmospheric pressure, a cylindrical horizontally disposed pressure-tight shell having an inlet at one end for gas under pressure and an outlet for said gas at its other end, a cooling coil arranged in said shell and having legs extending lengthwise thereof and having an inlet and an outlet extending through said shell, 2. series of transversely extending generally rectangular fin plates fast to the legs of said cooling coil and forming an extended surface thereon, said fin plates being substantially smaller than the internal cross sectional area of said shell and having their upper end lower edges horizontally disposed, certain of said fin plates at spaced intervals along said cooling coil being extended upwardly to said shell and other of said fin plates intermediate said certain plates being extended downwardly to said shell, said extensions of said fin plates providing bailles deflecting the gas to pass back and forth a plurality of times transversely across said legs of said cooling coil, blocking ofi means preventing the bypassing of said gas around the sides of said finned coil, an antifreeze liquid spray pipe extending longitudinally through said shell and through openings provided in said upward extensions of said fin plates, nozzles on said spray pipe and directed downwardly against the fins of said cooling coil to prevent frosting thereof, and means arranged to withdraw said spray liquid from the bottom of said shell and recirculate it through said spray nozzles.

3. In apparatus for cooling and dehumidifying gas under substantially higher than atmospheric pressure, a cylindrical horizontally disposed pressure-tight shell having an inlet at one end for gas under pressure and an outlet for said gas at its other end, a cooling coil arranged in said shell and having legs extending lengthwise thereof and having an inlet and an outlet extending through said shell, a series of transversely extending generally rectangular fin plates fast to the legs of said cooling coil and forming an extended surface thereon, said fin plates being substantially smaller than the internal cross sectional area of said shell and having their upper and lower edges horizontally disposed, certain of said fin plates at spaced intervals along said cooling coil being extended upwardly to said shell and other of said fin plates intermediate said certain plates being extended downwardly to said shell, said extensions of said fin plates providing bafiles deflecting the gas to pass back and fortha plurality of times transversely across said legs of said cooling coil, blocking oif means preventing the bypassing of said gas around the sides of said finned coil, comprising a bar arranged between each pair of said downwardly extending extensions on each side of said finned coil and extending lengthwise of said shell and secured to the lower corners of the fin plates between said downwardly extending extensions and in closely spaced relation to said shell, an antifreeze liquid spray pipe extending longitudinally through said shell and through openings provided in said upward extensions of said fin plates, nozzles on said spray pipe and directed downwardly against the fins of said cooling coil to prevent frosting thereof, and means arranged to withdraw said spray liquid from the bottom of said shell and recircuate it through said spray nozzles.

4. In apparatus for cooling and dehumidifying gas under substantially higher than atmospheric pressure, acylindrical horizontally disposed pressure-tight shell having an inlet at one end for gas under pressure and an outlet for said gas at its other end, a cooling coil arranged in said shell and having legs extending lengthwise thereof and having an inlet and an outlet extending through said shell, a series of transversely extending generally rectangular fin plates fast to the legs of said cooling coil and forming an extended surface thereon, said fin plates being substantially smaller than the internal cross sectional area of said shell and having their upper and lower edges horizontally disposed, certain of said fin plates at spaced intervals along said cooling coil being extended upwardly to said shell and other of said fin plates intermediate said certain plates being extended downwardly to said shell, said extensions of said fin plates providing baffles deflecting the gas to pass back and forth a plurality of times transversely across said legs of said cooling coil, blocking off means preventing the bypassing of said gas around the sides of said finned coil, comprising a vertical plate arranged lengthwise of said shell on each side of said fin plates and in closely spaced relation to the vertical edges thereof and having its upper and lower edges arranged adjacent said shell to provide a straight sided vertical way through the center of said shell, an antifreeze liquid spray pipe extending longitudinally through said shell and through openings provided in said upward extensions of said fin plates, nozzles on said spray pipe and directed downwardly against the fins of said cooling coil to prevent frosting thereof, and means arranged to withdraw said spray liquid from the bottom of said shell and recirculate it through said spray nozzles.

5. In apparatus for cooling and dehumidifying gas under substantially higher than atmospheric pressure, an elongated pressure-tight shell having a removable end head and arranged with its axis horizontally disposed and having an inlet at one end for gas under pressure and an outlet for sai d gas at its opposite end, a cooling coil arranged in said shell and having legs extending lengthwise thereof and having an inlet and an outlet extending through said removable end head, transversely extending fin plates fast to the legs of said cooling coil and forming an extended surface thereon, certain of said fin plates at spaced intervals along said cooling coil being ex tended upwardly toward said shell and other of said fin plates intermediate said certain plates being extended downwardly toward said shell, said extensions of said fin plates providing bafiles deflecting the gas to pass back and forth a plurality of times transversely across said legs of said cooling coil and parallel with said fin plates,

11 18 an antifreeze liquid pipe extencilnglthfiough at: REFERENCES CITED removable end head and long ud na y oi as men through open provided m Sam upwndly mm igllowiis paznrzierenees are of record in the extending extensions of said fln plates, nozzles on M pipe and directed downwardly 5 UNITED STATES PATENTS sgsinst the fins of said cooling coil to prevent Number Name Dste frosting thereof, and means for withdrawlnx sa 1,079,005 Hm Nov. 10, 1013 spray liquid from the bottom oi. said shell and re- 1,001,713 Jordnn et :1. Dec. 20, 1932 circulatlnz it throu h said p y nozzles. sa 2,038,530 Bulkele! Apr. 2a, was finned ooil, spray pipe and removable end head 10 2,199,967 Biehowsky May 7, 1940 beinz removsble as s imit from said shell- 2,235,004 Ashley Mar. 18, 1041 2,273,004 Newton Feb. 17, 1942 KAIB- 2,378,004 wmmm June 26, 1945 2,891,244; Jsekson Dec. 18, 1945 

